CVE-2026-20940
Microsoft Windows 10 21H2 ≤ 10.0.19044.6809
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-20940 is a high-severity Untrusted Pointer Dereference (CWE-822) vulnerability in Microsoft Windows 10 21H2. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 39th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-20940 is a heap-based buffer overflow vulnerability in the Windows Cloud Files Mini Filter Driver, published on 2026-01-13T18:16:21.313. The issue, associated with CWE-822, carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high severity due to its potential for significant impact on affected systems.
A local attacker with low privileges (PR:L) can exploit this vulnerability through local access (AV:L) with low attack complexity (AC:L) and no user interaction (UI:N). Successful exploitation enables privilege escalation, granting the attacker high-level confidentiality (C:H), integrity (I:H), and availability (A:H) impacts without changing scope (S:U).
The Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20940 details mitigation strategies and available patches for this vulnerability.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-2120
Vulnerability Data
Heap-based buffer overflow in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover instances where untrusted data is turned into a pointer and dereferenced.
Validating all information inputs stops untrusted values from being accepted and converted into dereferenceable pointers.
Memory-protection mechanisms limit the damage from an invalid pointer dereference without stopping the root coding flaw.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly prevent introduction of untrusted pointer handling during development.
Runtime monitoring of software and data can detect adverse events resulting from exploitation of the weakness.
Vulnerability identification processes can discover instances of this weakness via code review or scanning.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect pointer-dereference flaws before release.
Secure development lifecycle includes pointer-safety practices that reduce untrusted pointer dereference risk.
Application security requirements can mandate validation of pointers obtained from untrusted sources.
Secure architecture principles discourage direct use of untrusted values as pointers.
Secure coding standards explicitly forbid dereferencing pointers derived from untrusted input.